Question: $ { \left[\begin{array}{rr}{0} & {-1} \\ {0} & {1}\end{array}\right]-\left[\begin{array}{rr}{0} & {1} \\ {0} & {-1}\end{array}\right] = {?} } $
Explanation: To find the difference of two matrices, subtract the corresponding items between each matrix. ${\left[\begin{array}{rr}{0}-{0} & {-1}-{1} \\ {0}-{0} & {1}-{-1}\end{array}\right]}$ Now, simplify: ${\left[\begin{array}{rr}{0} & {-2} \\ {0} & {2}\end{array}\right]}$